Physics Unit6: Work and Energy - 题库网 (tiku.one)

1#

What is the correct und;w,rmn plk52 mf dy2-it of work expressed in SI units?

A. $kg m/s^2$

B. $kg m^{2}/s$

C. $kg m^{2}/s^2$

D. $kg^2 m/s^2$

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2#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Can work be done on a system if 09.zibr cpi3ky+qc (n there is no motion?

A. Yes, if an outside force is provided.

B. Yes, since motion is only relative.

C. No, since a system which is not moving has no energy.

D. No, because of the way work is defined.

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3#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If you push twice as h9j vrvq d1d7lo5*:.yh(p dgo)v1gt fdard against a stationary brick wall, the amount of work you :tyodo9vh (1 l7.v1dg)j *dqpvfrdg 5 do

A. doubles.

B. is cut in half.

C. remains constant but non-zero.

D. remains constant at zero.

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4#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 50-N object was lifted 2.0 m vertically and is bex5; d k xfp*04qzfwxn3 dlhv;1ing held there. How much work is being done in holding the boz ;0f ;xxwxdqhf1v k5p3l4dn*x in this position?

A. more than 100 J

B. 100 J

C. less than 100 J, but more than 0 J

D. 0 J

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5#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If you walk 5.0 m horizontally forward at a constant velocity carryin 0a3.bfvb 3r2bni 5uayg a 10-N object, the amount of work yu23r.a 0an3by5vb if bou do is

A. more than 50 J.

B. equal to 50 J.

C. less than 50 J, but more than 0 J.

D. zero.

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6#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A container of water is lifted v26seq9)l + fu:b6daj mg*,sa3ol qc ijertically 3.0 m then returned to its original position. If the total weight is 303os2l u)qqm+9: besl a6ij,ajf6*cd g N, how much work was done?

A. $45 \; J$

B. $90 \; J$

C. $180 \; J$

D. No work was done.

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7#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Does the centripetal force actinnwf(ra--;pww g on an object do work on the object?

A. Yes, since a force acts and the object moves, and work is force times distance.

B. Yes, since it takes energy to turn an object.

C. No, because the object has constant speed.

D. No, because the force and the displacement of the object are perpendicular.

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8#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

You throw a ball straight uei.v t sxu- +i54mqc0fp. Compare the sign of the work done by gravity while the ball goes up with the sign of the wo+ 5tvcsxu-f ii4 0eqm.rk done by gravity while it goes down.

A. Work is + on the way up and + on the way down.

B. Work is + on the way up and - on the way down.

C. Work is - on the way up and + on the way down.

D. Work is - on the way up and - on the way down.

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9#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The area under the curve, on a Force versus positiokzix jqlx/f,e 1t l*4+n (F vs. x) graph, representst+4 1k/qelfiz, xjl* x

A. work.

B. kinetic energy.

C. power.

D. potential energy.

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10#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

On a plot of Force versus position (F vs. x), gbiv*./s quz 9what represents the work done by the9q/uvsi gb .z* force F?

A. the slope of the curve

B. the length of the curve

C. the area under the curve

D. the product of the maximum force times the maximum x

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11#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The quantity $\frac{1}{2} \; mv^2$ is

A. the kinetic energy of the object.

B. the potential energy of the object.

C. the work done on the object by the force.

D. the power supplied to the object by the force.

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12#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If the net work done on an ol rqyqstdh)m/fxmsi t30*/ k8t-cy)3 bject is positive, then the object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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13#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If the net work done on an object is negativek2 mvqo4*i)h 6uf 1dmtto2m:-cj-b9v/fu eso, then the object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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14#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If the net work done on an object is zero, then the object's kinetic energyewp; i(pxoz jvj .zqv0;7 hs1(

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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15#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A truck weighs twice as much as a car, and is moving at twice the speed of 1u:3za6y; l hwq b: m c:vyy1ifrfu:(xthe car. Which statemy wx1az(:fq1vf::imu6l;yu: rbcyh 3ent is true about the truck's kinetic energy compared to that of the car?

A. All that can be said is that the truck has more kinetic energy.

B. The truck has twice the kinetic energy of the car.

C. The truck has 4 times the kinetic energy of the car.

D. The truck has 8 times the kinetic energy of the car.

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16#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Car J moves twice as fast as car K, and car J has half thmvcnq ; dw4*a1e mass of car K. The kinetic energy of car J, compared to ca1 ;cvn*md qw4ar K is

A. the same.

B. 2 to 1.

C. 4 to 1.

D. 1 to 2.

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17#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object hits a wall and bounces back with half of its original l+t0+pqpc h/j speed. What is the ratio of the final kinetic energy to the initial kinetic energyq tpp/l +c0+jh?

A. \frac{1}{2} \;

B. 1/4

C. 2

D. 4

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18#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A brick is moving at a speed of 3 m/s and hl0 2.rbm7 ncya tr+d,a pebble is moving at a speed of 5 m/s. If both objects have the same kinetic energy, what is the ratio of thh0+b, mrac.2tn7dl yre brick's mass to the rock's mass?

A. 25 to 9

B. 5 to 3

C. 12.5 to 4.5

D. 3 to 5

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19#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 4.0-kg mass is moving with s 6))uoybmh7 scpeed 2.0 m/s. A 1.0-kg mass is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. moh6 ))s7 cbuy Which object travels the greater distance before stopping?

A. the 4.0-kg mass

B. the 1.0-kg mass

C. Both travel the same distance.

D. cannot be determined from the information given

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20#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

You slam on the brakes of your car in a panic, and skid a certain distance ol,.r7sagv(b 6,pw 4yqdmdjq7n a straight, level road. If you had been traveling twice as fast, what distance would the car have skidded, under the same condition (ra gdly 7qj6m7dbw p,q,vs4.s?

A. It would have skidded 4 times farther.

B. It would have skidded twice as far.

C. It would have skidded 1.4 times farther.

D. It is impossible to tell from the information given.

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21#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A planet of constant mass orbits the Sun in an elliptical orbit. N 7 u2rscjm51s qgqy hw/9z,n:neglecting any fricqz :cm,2ugsnj7s /wn 519qhy rtion effects, what happens to the planet's kinetic energy?

A. It remains constant.

B. It increases continually.

C. It decreases continually.

D. It increases when the planet approaches the Sun, and decreases when it moves farther away.

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22#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the work-energy aukr7f6nlt1 3*wn5swfi8f i0vb0 hb+ principle.

该题自我估分: (必填) (满分:1.0分)

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23#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The quantity mgy is

A. the kinetic energy of the object.

B. the gravitational potential energy of the object.

C. the work done on the object by the force.

D. the power supplied to the object by the force.

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24#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The quantity $\frac{1}{2} \; kx^2$ is

A. the kinetic energy of the object.

B. the elastic potential energy of the object.

C. the work done on the object by the force.

D. the power supplied to the object by the force.

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25#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Is it possible for a system tog : r(-qdad1 ujh-ygk/ have negative potential energy?

A. Yes, as long as the total energy is positive.

B. Yes, since the choice of the zero of potential energy is arbitrary.

C. No, because the kinetic energy of a system must equal its potential energy.

D. No, because this would have no physical meaning.

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26#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object is released from rest a height h above the ground. A secg8r ,b+2:udsv wn7ix t kuz3:fond object with four times the mass of tzugf7 2kdw, +vbn3i8xu:t:rshe first if released from the same height. The potential energy of the second object compared to the first is

A. one-fourth as much.

B. one-half as much.

C. twice as much.

D. four times as much.

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27#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 0.200-kg mass attached to the end of a spring causes it to stretch 5.0 cm. I knha b(ew; z5q b,ug;+s7x1zlf another 0.200-kg mass is added to the spring, the potential ene;;q5x1shlbg(zk+7ew , ua n bzrgy of the spring will be

A. the same.

B. twice as much.

C. 3 times as much.

D. 4 times as much.

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28#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The total mechanical energy zades )7xrl8 0k:(e vdof a system

A. is equally divided between kinetic energy and potential energy.

B. is either all kinetic energy or all potential energy, at any one instant.

C. can never be negative.

D. is constant, only if conservative forces act.

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29#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An acorn falls from a tree. Co(a p5g,xoq9x0 8l8)l sy h fffeldn3l*mpare its kinetic energy K, to its potential energy Uyg5s ho0llxx)*(lqe 3 ,nflf9pd 8fa8.

A. K increases and U decreases.

B. K decreases and U decreases.

C. K increases and U increases.

D. K decreases and U increases.

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30#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Describe the energy of a car driving uz1; ump 5xb,dkp a hill.

A. entirely kinetic

B. entirely potential

C. both kinetic and potential

D. gravitational

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31#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A lightweight object and a very heag ibrkd+s(m50 vy object are sliding with equal speeds along a level frictionless surface. Thr5sbi 0mk +d(gey both slide up the same frictionless hill. Which rises to a greater height?

A. The heavy object, because it has greater kinetic energy.

B. The lightweight object, because it weighs less.

C. They both slide to the same height.

D. cannot be determined from the information given

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32#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Consider two masses w1dy/nw,; hd. pbrhu f4:w .ky$m_{1}$ and $m_{2}$ at the top of two frictionless inclined planes. Both masses start from rest at the same height. However, the plane on which $m_{1}$ sits is at an angle of $30^{\circ}$ with the horizontal, while the plane on which $m_{2}$ sits is at $60^{\circ}$. If the masses are released, which is going faster at the bottom of its plane?

A. $m_{1}$

B. $m_{2}$

C. They both are going the same speed.

D. cannot be determined without knowing the masses

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33#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the principle of conservation of mechanical energy for conserdx .xpjcyq) u5zp9n) 2vative forcesp )qp.dc2x uynj )59xz.

该题自我估分: (必填) (满分:1.0分)

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34#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A ball falls from the top of a building, through the air (air frictio5ar9 snypz0 x+n is present), to the ground below. How does the kinetic energy (K) just before striking the ground compare to the potential en5+spy0 anrzx9ergy (U) at the top of the building?

A. K is equal to U.

B. K is greater than U.

C. K is less than U.

D. It is impossible to tell.

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35#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A ball drops some distance and gains 30 J of kinev,ffn7i; 4mc3;u2kb-ohw n.dlpnn7awg- k 0 mtic energy. Do not ignore air resistance. How much gravitational potential energy did the ball lou i;h;b4f--m dpc, vfn7gnlk3n. k02moa7wwn se?

A. more than 30 J

B. exactly 30 J

C. less than 30 J

D. cannot be determined from the information given

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36#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A ball drops some distance and loses 30 J of gravitationgynb9b 8s qn ya(.nj:9al potential energy. Do not ignorsnb n9:9.8aqbgnyyj (e air resistance. How much kinetic energy did the ball gain?

A. more than 30 J

B. exactly 30 J

C. less than 30 J

D. cannot be determined from the information given

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37#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the law of conservation of e ejkx iunst ).o1k94a/nergy.

该题自我估分: (必填) (满分:1.0分)

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38#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The quantity Fd/t ispw t7dt1bbf) 5

A. the kinetic energy of the object.

B. the potential energy of the object.

C. the work done on the object by the force.

D. the power supplied to the object by the force.

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39#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What is the correct unit of powert5+:ri hd vlvwbm 6,i, expressed in SI units?

A. $kg m/s^2$

B. $kg m^{2}/s^2$

C. $kg m^{2}/s^3$

D. $kg^2 m/s^2$

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40#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Of the following, which is not a unit )d+.n).z,s hgawb/t ox bqrk) of power?

A. watt/second

B. newton-meter/second

C. joule/second

D. watt

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41#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Compared to yesterday, you did 3 times the work in one9 *t9x6mqfyyhz* vqo6-third the time. To do so, your power output must have 6*yzotx9q 9*6yfhv qm been

A. the same as yesterday's power output.

B. one-third of yesterday's power output.

C. 3 times yesterday's power output.

D. 9 times yesterday's power output.

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42#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

To accelerate your car at a constant acceleratabl8a id. -pd 2b,yg-oion, the car's engine must

A. maintain a constant power output.

B. develop ever-decreasing power.

C. develop ever-increasing power.

D. maintain a constant turning speed.

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43#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object is lifted vertically 2.0 m and helb8)5rcux m 8ldd there. If the object weighs 90 N, how 5ml)rcux bd8 8much work was done in lifting it?

A. $360 \; J$

B. $180 \; J$

C. $90 \; J$

D. $0 \; J$

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44#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

You lift a 10-N physics zd/ m+w 6pesfxl e2*9mbook up in the air a distance of 1.0 m, at a constant velocity *zx+sm2eep / wdlfm69of 0.50 m/s. What is the work done by the weight of the book?

A. +10 J

B. -10 J

C. +5.0 J

D. -5.0 J

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45#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 500-kg elevator is pulled upward with a czdxc13,ngtizyy;) 8ecr :s)tpm ;-iconstant force of 5500 N for a distance of 50.0 m. What is the work done by ytx;es i81 t:,-)c yzirdc3zn)m g;p cthe 5500 N force?

A. $2.75 \times 10^{5} \; J$

B. $-2.45 \times 10^{5} \; J$

C. $3.00 \times 10^{4} \; J$

D. $-5.20 \times 10^{5} \; J$

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46#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 500-kg elevator is pulled upward with a constant force of 5500 N fn skx qdf ry8 jz5n1cmq,)2l:)or a distance of 50.0 m. What is the work done by the weight o rqz nd2jsn1m)fc,k8 xl5y)q:f the elevator?

A. $2.75 \times 10^{5} \; J$

B. $-2.45 \times 10^{5} \; J$

C. $3.00 \times 10^{4} \; J$

D. $-5.20 \times 10^{5} \; J$

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47#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 500-kg elevator is pulled upward with a constant force of 558c 98rlq qd0ka 5wunc300 N for a distance of 50.0 m. What is the net wow08cdkq8 n5a9u q r3lcrk done on the elevator?

A. $2.75 \times 10^{5} \; J$

B. $-2.45 \times 10^{5} \; J$

C. $3.00 \times 10^{4} \; J$

D. $-5.20 \times 10^{5} \; J$

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48#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 30-N box is pulled ru,sgv2o*nl;gj b 69k 6.0 m up along a $37^{\circ}$ inclined plane. What is the work done by the weight (gravitational force) of the box?

A. $-11 \; J$

B. $-1.1 \times 10^{2} \; J$

C. $-1.4 \times 10^{2} \; J$

D. $-1.8 \times 10^{2} \; J$

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49#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 4.00-kg box of fruit sajz6v) r:,5j.c mxmdzlides 8.0 m down a ramp, inclined at $30^{\circ}$ from the horizontal. If the box slides at a constant velocity of 5.00 m/s, what is the work done by the weight of the box?

A. $157 \; J$

B. $-157 \; J + 78.4 \; J$

C. $78.4 \; J$

D. $-78.4 \; J$

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50#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Matthew pulls his lit biix, 0-k*wk a9zna4utle sister Sarah in a sled on an icy surface (assume no friction), with a force ou aab490 kw-x,*k iznif 60.0 N at an angle of $37^{\circ}$ upward from the horizontal. If he pulls her a distance of 12.0 m, what is the work done by Matthew?

A. $185 \; J$

B. $433 \; J$

C. $575 \; J$

D. $720 \; J$

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51#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the direction of the force. The graphm)lni22afiph fgr7k ;g )7e k; in Fig. 6-1 shows the force versus the object's position. Find the work done when the object moves from 0 h lp 2;7a2efr; kgnfim7g)k) ito 2.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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52#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object e2m-a*+twv ea in the direction of the force. The graph in Fig. 6-1 shows the force versus 2eaaw * vm+te-the object's position. Find the work done when the object moves from 2.0 to 4.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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53#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the direction of the for+2lo o;gay4s tce. The graph in Fig. 6-1 shows the force versus the object's poy+2 t4ls;aoogsition. Find the work done when the object moves from 4.0 to 6.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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54#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the direction of the force. The graph in Fig.eux8pb a.idc5nt02qb5 0+sgi 6-1 show+.pi5 tc0qu8 5isxgda0b e2bns the force versus the object's position. Find the work done when the object moves from 0 to 6.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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55#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A horizontal force of 200 N is applied to molcme1:q0rl6n wf/n 4lve a 55-kg cart (initially at rest) across a 10 m level surface. What is the final ki1q4c 0f/l6 elnwmrnl :netic energy of the cart?

A. $1.0 \times 10^{3} \; J$

B. $2.0 \times 10^{3} \; J$

C. $2.7 \times 10^{3} \; J$

D. $4.0 \times 10^{3} \; J$

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56#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A horizontal force of 200 N is applied to move a 55-kg cart (initially at rx*n/+kjg slxe+zsw*3est) across a 10 m level surface. What is the final speed s+sjzxk3*l +x w *g/enof the cart?

A. 73 m/s

B. 36 m/s

C. 8.5 m/s

D. 6.0 m/s

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57#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10-kg mass is moving with a speed of 5.0 m/s. How much work is required to sq1 g m fxs6(+8u;xb pa19llznxtop theapxl 9+n81f ms;6zqlb(xg 1xu mass?

A. $50 \; J$

B. $75 \; J$

C. $100 \; J$

D. $125 \; J$

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58#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If it takes 50 m to stop a car initun7j+6+yaku4 6l)rp *4hox+g txxqylially moving at 25 m/s, what distance is required to stop a l+uxgxt 4rx+ hjl7 nuo4+qa*y6y6 k) pcar moving at 50 m/s under the same condition?

A. $50 \; m$

B. $100 \; m$

C. $200 \; m$

D. $400 \; m$

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59#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A spring-driven dart g*h :: *lbeja1h 9fpxblun propels a 10-g dart. It is cocked by exerting a force of 20 N over a distance of 5.0 cm. With what speed will the dart leave the gun, assuming the spring has ne:pb:9*1 *lexah j lbfhgligible mass?

A. 10 m/s

B. 14 m/s

C. 17 m/s

D. 20 m/s

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60#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 100-N force has a horv031rw. ohw;*u gox4midv yy9izontal component of 80 N and a vertical component of 60 N. The force is applied to a box which rests on a level frictionless floor. The cart starts from rest, and moves 2.0 m hv9o u*y.rmv g3w4y0 wh1i;odx orizontally along the floor. What is the cart's final kinetic energy?

A. $200 \; J$

B. $160 \; J$

C. $120 \; J$

D. zero

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61#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An arrow of mass 20 g is shot horizontally into a 67ia3mifo t)vg75q/:k tx)ae3 mkkop bale of hay, striking the hay with a velocity of 60 m/s. It pefa5xiok i)g3o m73e)/mt:k at6v7p kqnetrates a depth of 20 cm before stopping. What is the average stopping force acting on the arrow?

A. $45 \; N$

B. $90 \; N$

C. $180 \; N$

D. $360 \; N$

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62#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 15.0-kg object is moved from a height of 7.00 m above a floor to a height of ee6yce9;o 6vv13.0 m above the floor. What is the change in9 ev6;oy eec6v gravitational potential energy?

A. zero

B. 1030 J

C. 1176 J

D. 1910 J

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63#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 400-N box is pushed up an inclined plane. The plane is 4.0 m long andh;ly m/8vte, w rises 2.0 m. If the plane is frictionless, how much work was done by the yw h/vm8e;,ltpush?

A. $1600 \; J$

B. $800 \; J$

C. $400 \; J$

D. $100 \; J$

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64#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10-kg mass, hung onto a spring, causes the spring t20-wbmgy //3maxw fivo stretch 2.0 cm. What is the spv/b mi3wf2/- xayw m0gring constant?

A. $4.9 \times 10^{3} \; N/m$

B. $5.0 \times 10^{3} \; N/m$

C. 20 N/m

D. 2.0 N/m

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65#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A spring is characterized by xxdc,1: jgm9h1/ d zjua0z yv wxh4k;(a spring constant of 60 N/m. How much potential energy does it stou10;chx ,xdmzh1x4/gjwk dj: (az9yvre, when stretched by 1.0 cm?

A. $3.0 \times 10^{-3} \; J$

B. $0.30 \; J$

C. $60 \; J$

D. $600 \; J$

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66#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Calculate the work required to compress an initial7izhnhe7-u5 wm y+ n(qly uncompressed spring with a y7m( 7neqw5nz+iuhh -spring constant of 25 N/m by 10 cm.

A. $0.10 \; J$

B. $0.13 \; J$

C. $0.17 \; J$

D. $0.25 \; J$

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67#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What work is required to stretch a spring of spring constcsoq0y)kw45y fwk .d2ant 40 N/m from x = 0.20 m to 0.25 m? (Ass)k 0os.ykw2wdq f5y4cume the unstretched position is at x = 0.)

A. $0.45 \; J$

B. $0.80 \; J$

C. $1.3 \; J$

D. $0.050 \; J$

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68#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A spring with a spring constant of 15 N/m is inhr-+ t;t t gzv7y(dc3uitially compressed by 3.0 cm. How much work is required to compress the spring an ; 7tc(g r3d-uy+thtvzadditional 4.0 cm?

A. $0.0068 \; J$

B. $0.012 \; J$

C. $0.024 \; J$

D. $0.030 \; J$

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69#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 60-kg skier starts from rest from the top of 6bqzkpp,b (a 2a 50-m high slope. What is the speed of the skier on reaching the bottom of the slope? (neglec(akqzp,p6b 2bt friction)

A. 22 m/s

B. 31 m/s

C. 38 m/s

D. 41 m/s

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70#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A skier, of mass 40 kg, pushes off the top of a hill with an initial s0x -npo+dt,wlwxe :v(peed of 4.0 m/s. Neglecting friction, how fast wi 0,xo+:twxwd(le np v-ll she be moving after dropping 10 m in elevation?

A. 7.3 m/s

B. 15 m/s

C. 49 m/s

D. 196 m/s

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71#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object slides down5 *b ei hg+dfjhimo*-3 a frictionless inclined plane. At the bottom, it has a speed of 9.80 m/sdbojiim* f* e3h5 -hg+. What is the vertical height of the plane?

A. $19.6 \; m$

B. $9.80 \; m$

C. $4.90 \; m$

D. $2.45 \; m$

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72#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1.0-kg ball falls to the floor. When it is 0.70 m above the fg mx5ykks,qn4/3+jk y loor, its potential energy exactly equals its kinetic energy. How fast is it movingks+yqy 4xm 5,3kjkgn/?

A. 3.7 m/s

B. 6.9 m/s

C. 14 m/s

D. 45 m/s

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73#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A toy rocket, weighing 10 N, blasts straight up from groundu,s8/nri*yde level with a kinetic energy of 40 J. At the exact top of its trajectory, its i*yd8 eur/ s,ntotal mechanical energy is 140 J. To what vertical height does it rise?

A. $1.0 \; m$

B. $10 \; m$

C. $14 \; m$

D. $24 \; m$

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74#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A projectile of mass m leaves the ground with a kinetic energy of 220 J. :/vjww s wosz:k0*pjz 7i /,iq At the highest point in its trajectory, its kinetic energy is 120 J. To what vertical height, r*io s:sjq:0/, v 7ijzw/wkwz pelative to its launch point, did it rise?

A. $\frac{220}{mg} \; m$

B. $\frac{120}{mg} \; m$

C. $\frac{100}{mg} \; m$

D. Impossible to determine without knowing the angle of launch

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75#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A roller coaster starts from rest at a a5yj7s3 .6mntyds1 jw point 45 m above the bottom of a dip (See Fig. 6-2). Neglect friction, whatw sy7jn15ymdt3ja.6s will be the speed of the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip?

本题所包含的其它图片:

A. 14 m/s

B. 17 m/s

C. 24 m/s

D. 30 m/s

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76#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A roller coaster starts with a i njej4tf49xz* (u v4atio *gz0z+km/speed of 5.0 m/s at a point 45 m above the bottom of a 9enm+4itzzx4*u o04fi*(tjvg z ja/ k dip (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip?

本题所包含的其它图片:

A. 12 m/s

B. 14 m/s

C. 16 m/s

D. 18 m/s

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77#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A roller coaster starts at a(2w9 cy:;;eshuspve z point 30 m above the bottom of a dip with a speed of 25 m/s (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which u (ys;vc9h;e pwe s2:zis 45 m above the bottom of the dip?

本题所包含的其它图片:

A. 14 m/s

B. 16 m/s

C. 18 m/s

D. 20 m/s

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78#

( 1.0 分) 切至整卷模式搜藏此题

What is the minimum speed of the ball at the bottomc,uagi/ehs 6:l /oisp2jh)k+mr m v/- of its swing (point

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79#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A:2.2 m/s

A. 3.1 m/s

B. 4.4 m/s

C. 4.9 m/s

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80#

( 1.0 分) 切至整卷模式搜藏此题

难度:2

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81#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2-kg pendulum of length 50 cm is pulled 0.19 m away from0l.0mm dk 5ofv the vertical axis and released from resk.0m fo 50vmdlt. What will be its speed at the bottom of its swing?

A. 0.257 m/s

B. 0.686 m/s

C. 1.03 m/s

D. 0.857 m/s

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82#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1500-kg car moving at 25 m/s hits an initially uncomb(me e,6,7mxk vdd9h rpressed horizontal spring withb7mme k9dxh6(,ed, v r spring constant of $2.0 \times 10^6 \; N/m$. What is the maximum compression of the spring? (Neglect the mass of the spring.)

A. $0.17 \; m$

B. $0.34 \; m$

C. $0.51 \; m$

D. $0.68 \; m$

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83#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A driver, traveling at 22 m/s, slows down her 2000 kg car to stop for a rnpz;7xrl xf(;ed light. What work is done by the friction force ;prx(z;l7 xfn against the wheels?

A. $-2.2 \times 10^{4} \; J$

B. $-4.4 \times 10^{4} \; J$

C. $-4.84 \times 10^{5} \; J$

D. $-9.68 \times 10^{5} \; J$

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84#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The kinetic friction force between a 60.0-kg object and a horizontal surface isoakm(-h.8xu z 0l-yks14ezvg 50.0 N. If the initial ekx8 ho- .1 ( zyavm4k-zg0sulspeed of the object is 25.0 m/s, what distance will it slide before coming to a stop?

A. $15.0 \; m$

B. $30.0 \; m$

C. $375 \; m$

D. $750 \; m$

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85#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 12-kg object is moving on ,nv9s.xbf ts;)zynw(3x3bdm8 ap;)gkjw 9 yx a rough, level surface. It has 24 J of kinetic energy. The friction force on it 9na3;; g(9byzpy8w) jb.s) vfxtx,dnxmks3wis a constant 0.50 N. How far will it slide?

A. $2.0 \; m$

B. $12 \; m$

C. $24 \; m$

D. $48 \; m$

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86#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force of 10 N is applied horizontally to a 2.0-kg mass on ah6pli ;v q4 w;x3agl.z fvm gv9x/k/-o level surface. The coep9vw3/ggvzfoxx; i/h- l;m 46alqkv .fficient of kinetic friction between the mass and the surface is 0.20. If the mass is moved a distance of 10 m, what is the change in its kinetic energy?

A. $20 \; J$

B. $39 \; J$

C. $46 \; J$

D. $61 \; J$

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87#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 60-kg skier starts from rest from the top of a 50-m high /aaa wb6,vh 0eslope. If the work dob/aa6 evw 0ah,ne by friction is $-6.0 \times 10^{3} \; J$, what is the speed of the skier on reaching the bottom of the slope?

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88#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An 800-N box is pushed u -w;-t mbzcur67l.hdg p an inclined plane. The plane is 4.0 m long and rises 2.0 m. It requires 3200 J of work to get the box to the top ofc6lg.m zr tdw-;u 7h-b the plane. What was the magnitude of the average friction force on the box?

A. $0 \; N$

B. non-zero, but less than 400 N

C. $400 \; N$

D. greater than 400 N

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89#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2.0-kg mass is releo aa:7vo 3-k zl.8zh q66bxcyyased from rest at the top of a plane inclined at 20e above horizontal. The coefficient of kinetic friction between the mass and the plane is 0.20. What will be the speed of the mass after slidingyzlkyh8b:6x6v7. za o-caq o3 4.0 m along the plane?

A. 2.2 m/s

B. 3.0 m/s

C. 3.5 m/s

D. 5.2 m/s

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90#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 30.0-N stone is dropped from a height of 10.0 0vs,ty78( p0b:w uckq 90.jrruwmg ckm, and strikes the ground with a velocity of 7.00 m/s. What average force of air frictirqk 0gk8ym,wj0u.0vb(u:c w7 9sp ctron acts on it as it falls?

A. $22.5 \; N$

B. $75.0 \; N$

C. $225 \; N$

D. $293 \; N$

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91#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

At what rate is a 60.0-kg boy using energy when he runs up wd) q)3ox6 ci*c+dgs2z mecb/a flight of stairs 10.0-m higqci+ g zd* c oc2m)swd/eb)36xh, in
8.00 s?

A. $75.0 \; W$

B. $735 \; W$

C. $4.80 \; kW$

D. $48 \; W$

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92#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10-N force is needed to move an object with a constant velocit q b)23kc ngi ou+n*zq,nymjc x)sz419y of 5.0 m/s. What power mu)j)ogx9 uck4 mnb+z*y1 ,nz s2niq q3cst be delivered to the object by the force?

A. $0.50 \; W$

B. $1.0 \; W$

C. $50 \; W$

D. $100 \; W$

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93#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

How many joules of energy are used by a 1.0 h a40by+1vhh yqy2zh640 u exjxp motor that runs for 1.0 hr? (1 hp = 746 j4hxhy2b+x1z04a6u y v0q e yhW)

A. $3.6 \times 10^{3} \; J$

B. $2.7 \times 10^{6} \; J$

C. $4.5 \times 10^{4} \; J$

D. $4.8 \; J$

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94#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A cyclist does work at the rate ofj)) +7cmy5x wl taj;,aisott+*4yqlhqe 8o y8 500 W while riding. How much force does her foot push with wh4lxyw+ t8q)8 y +tsy7j;aqaieo5*mohj, lc) ten she is traveling at 8.0 m/s?

A. $31 \; N$

B. $63 \; N$

C. $80 \; N$

D. $4000 \; N$

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95#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1500-kg car accelerates from 0 to 25 m/s in 7.0 s. What is the ayy2x7t5+lpq9jh 9zmf verage power delivered by the engine? (1 hp = 746 W)l59tq+72yz yp mh9 fjx

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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31	32	33	34	35	36	37	38	39	40
41	42	43	44	45	46	47	48	49	50
51	52	53	54	55	56	57	58	59	60
61	62	63	64	65	66	67	68	69	70
71	72	73	74	75	76	77	78	79	80
81	82	83	84	85	86	87	88	89	90
91	92	93	94	95

1	2	3	4	5	6	7	8	9	10
11	12	13	14	15	16	17	18	19	20
21	22	23	24	25	26	27	28	29	30
31	32	33	34	35	36	37	38	39	40
41	42	43	44	45	46	47	48	49	50
51	52	53	54	55	56	57	58	59	60
61	62	63	64	65	66	67	68	69	70
71	72	73	74	75	76	77	78	79	80
81	82	83	84	85	86	87	88	89	90
91	92	93	94	95